Dont think he wants to wait that long, Dan. GM Dealer should have it. NAPA might have it, or should be able to match it as well out of their assortment box, if push comes to shove.

Well thanks guys, I replaced the O ring with a temporary one I had around, but about 20 mins into my test drive it started belching white steam. I guess I'm one of those wanna be home mechanics that really screwed up lol. I believe the intake was over torqued, and probably cracked. If anyone has the actual torque lbs/nm that would be awesome, A sequence couldn't hurt either. The problem was we found about 3 different recommended torques,plus 2 sequences, and we used 30, then i learned the one i trusted most was 24lbs. We seen 30, 24 and 11. 11 seemed light, and I'm not terribly experienced with this type of car issues, so it'* live and learn i guess ha-ha. Any tips would be appreciated. :(

Everything is right here.

https://www.gmforum.com/t278911/

Well we opened it back up LIM is ok, and last time we changed only the front head gasket. We found it was in perfect condition, and didn't replace the rear one. The car ran great for 2 15 min test drives, and when i went home all proud and took the missus for a ride, it started belching massive white clouds. Now we are back to square one. Could it be the rear head gasket. Please say no.

Possible, but not likely. Head gaskets on these engines don't blow very often.

So if one head gasket is new and properly torqued, and the other is most likely fine, and we did the LIM, and it looks fine also. It was admittedly over torqued, but its looks perfectly fine. what might be causing the sputtering and eventual engine filling with anti freeze. It'* 100% internal and didn't leak right away. This tells me we must have had our hands on the issue at one point. But even right after the fix the exhaust was white and stinky. We assumed it was the car cleaning out the crap left in it that we couldn't get, and took it for a rip or two.Then literally about 10 houses from mine it started to sputter, we decided to idle around the block to see wtf. We looked behind us, and there was giant plumes of white smoke.
This car is really starting to get my goat, I got some major buyers remorse right now. Ha-Ha

Any help would be awesome, even wild stabs in the dark would do at this point. Oh and sorry for n00bing up your forums

Is this engine supercharged? If so you used a new gasket, but did you use new O rings between the LIM and supercharger? That would leak right in to your LIM.

No the engine isn't supercharged, and the only gasket we reused was the plenum as there was very recent work done to the car. Most likely to temporarily hide the tragic flaws, and it was brand new looking, in very good shape. So far the plan seems to be to open that rear head and see whats up back there, i have the 2nd head gasket, so its not much of a pain for me outside of the extra work. I don't want to open it though, since it seems heads are a rare issue. It'* hard to decide how to handle this, as it was still puking white clouds after the fix. I cannot tell if we never fixed anything, or if it was just cleaning itself out. At the end though, it was undeniably worse. I fumigated 2 blocks with pure white exhaust.

Well, seeing that you have the gasket and already did the front. You may as well do the back just to clear your mind. Post pictures if you find anything.

Yeah, that'* pretty much what we were figuring too... not the answer I wanted, but it'* the one I assumed I would get.(heavy sigh). This cars pretty lucky it had a few days to spoil me with its luxury. I'm at the end of rope after this though, then its time to kill it with fire!